FIG. 1 is a block diagram showing the construction of a conventional home network system, and FIG. 2 is a block diagram showing the construction of each home appliance provided in the conventional home network system.
As shown in FIGS. 1 and 2, the conventional home network system comprises a plurality of home appliances 2 and 3 connected to a power line 1, which supplies operating power, and a home server 5 for exchanging information with the home appliances 2 and 3 over a network line 4 connected therewith and controlling each of the home appliances 2 and 3 in response to an associated external home appliance control signal.
Each of the home appliances 2 and 3, which are connected to a home network via the power line 1 and network line 4, includes a load 6 for operating the corresponding home appliance, such as a motor, a controller 7 for analyzing data inputted from the network line 4 and outputting a signal for control of the operation of the load 6 in accordance with the analyzed result a low voltage transformer (referred to hereinafter as “LVT”) 8 for supplying a drive voltage to the controller 7, and a relay 9 for turning on/off the load 6 in response to the control signal from the controller 7.
A description will hereinafter be given of the operation of the conventional home network system with the above-mentioned construction.
The home server 5 is connected with an external communication network to control various home appliances in a home and exchange information therewith from time to time. The plurality of home appliances 2 and 3 are connected with the home server 5 via the network line 4 to exchange information therewith, and also to the power line 1 to receive the operating power therefrom.
In the case where a power plug (not shown) of each of the home appliances 2 and 3 is inserted into a receptacle (not shown), an alternating current (AC) voltage from the power plug is applied to the LVT 8 over the power line 1.
Upon receiving information or a control signal from the home server 5 over the network line 4, the controller 7 analyzes the received information or control signal and outputs a control signal in accordance with the analyzed result to control the load 6, such as the motor.
In response to the control signal from the controller 7, the relay 9 is turned on/off to turn on/off the load 6 so as to operate/stop the corresponding home appliance connected to the home network.
At this time, if the home appliance 2 or 3 is in operation, a considerable amount of power is continuously consumed therein. However, even when the home appliance 2 or 3 is in a standby mode where it is not in operation, the information exchange and monitoring must be performed between the home server 5 and the home appliance from time to time due to characteristics of the home network, thereby making it impossible to completely power off the home appliance.
In other words, the conventional home network system has a disadvantage in that a large amount of standby power, most of which is occupied by leakage current of the LVT 8, is consumed in the home appliance because the controller in the home appliance must always remain connected to the power line 1.
This problem has recently become a big issue in that many home appliances for the home network have been introduced to the market and the unplug campaign has become widespread due to a growing interest in power consumption reduction across all of society.